Reformat all gn files in /ash/system/machine_learning.

`gn format` recently changed its formatting behavior
for deps, source, and a few other elements when they
are assigned (with =) single-element lists to be consistent
with the formatting of updates (with +=) with single-element.

Now that we've rolled in a GN binary with the change,
reformat all files so that people don't get presubmit
warnings due to this.

This CL was uploaded by git cl split.

R=wrong@chromium.org

Bug: 1041419
Change-Id: I6759f2f2d88ecab9c71e220d6be9093720ba4a1a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1994079
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Thanh Nguyen <thanhdng@chromium.org>
Reviewed-by: Jia Meng <jiameng@chromium.org>
Commit-Queue: Jia Meng <jiameng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#731776}

ash/system/machine_learning/BUILD.gn

@@ -5,7 +5,5 @@
 import("//third_party/protobuf/proto_library.gni")
 
 proto_library("user_settings_event_proto") {
-  sources = [
-    "user_settings_event.proto",
-  ]
+  sources = [ "user_settings_event.proto" ]
 }